JAK2 rearrangement

Allogeneic hematopoietic stem cell transplantation was associated with improved prognoses in patients within the high-risk subgroup. In conclusion, this study identified a clinically distinct entity that possesses effective prognostic features and provides potential guidance for refining risk stratification in Ph-like ALL.

We also reviewed all cases with BCR::JAK2 rearrangement reported in the literature. In conclusion, a suspected t(9;22)/BCR::JAK2 rearrangement warrants further characterization with genomic assays such as OGM, whole chromosome sequencing, and RNA sequencing to explore other gene disruptions and/or rearrangements.

P1, N=15, Recruiting, University of Chicago | Trial completion date: Sep 2024 --> Sep 2027 | Trial primary completion date: Sep 2023 --> Sep 2026

In 8/15 patients ponatinib was used as single agent or in association with steroids or intrathecal chemotherapy only, in 4 it was administered in combination with chemotherapy and in 3 with blinatumomab; 7 patients started ponatinib after having failed an allogeneic transplant (6 hematologic relapses and 1 molecular relapse). In a pre-transplant setting, ponatinib was effective as a bridge to cellular therapies in 7 out of 8 patients as intention-to-treat (ITT), thus suggesting that this strategy may represent an effective bridge to further therapies. To our knowledge, this is the largest cohort of adult Ph-like ALL cases treated with ponatinib so far reported.

P2, N=10, Recruiting, William Shomali | N=25 --> 10 | Trial completion date: Oct 2023 --> Nov 2025 | Trial primary completion date: Apr 2023 --> Nov 2025

T-cell vitreoretinal lymphoma is rare, and diagnosis can be challenging. Despite inconclusive cytology in this case, interphase fluorescence in situ hybridization detected a JAK2 gene rearrangement, which confirmed the involvement by indolent T-cell lymphoproliferative disorder of the gastrointestinal tract and prompted appropriate treatment and workup for recurrent systemic or central nervous system lymphoma.

Additionally, 2 patients received ruxolitinib, 2 received allogeneic stem cell transplant, and 1 received CAR-T therapy...In summary, JAK2-R ALL occurs more often in adult males, are mostly of B-cell lineage, and associated with an aggressive clinical course. Absence of eosinophilia and bone marrow fibrosis and no evidence of preexisting/concurrent JAK2-R myeloid neoplasms distinguish JAK2-R ALL from other myeloid/lymphoid neoplasms with eosinophilia and JAK2-R.

No abstract available

Children with Ph-like ALL common genes were older than other high-risk B-ALL patients at diagnosis, with high white blood cells and lower survival rate. The bone marrow MRD not turning negative at the end of first induction were independent prognostic risk factor for children with Ph-like ALL common gene.

P1, N=15, Recruiting, University of Chicago | Trial primary completion date: Sep 2022 --> Sep 2023

In developing countries, detecting Philadelphia (Ph)-like B-lineage acute lymphoblastic leukemia is complicated and challenging due to its diverse genetic landscape. There is no well-defined and cost-effective methodology for its detection. The incidence of this high-risk subtype is very high in adult cases, and there is an urgent need for its accurate detection. We have developed an online PHi-RACE classifier for its rapid detection, followed by delineating the genomic and proteomic landscape of Ph-like acute lymphoblastic leukemias for the first time in Indian patients.

However, there have been great challenges in understanding their role in this pathogenesis. In this review, we will discuss the most recent literature and trends associated with JAK2 mutations in patients with B-ALL.

Patients with Ph-like ALL harboring JAK2 or EPOR rearrangements or IL7R indels routinely had higher LDA scores and levels of EOI MRD positivity versus those with the more common CRLF2-R subtype (Tasian ASH 2020 #1095). JAK2 rearrangements occurred most frequently amongst Cohort C patients, often with previously-unknown gene partners. Although 13/23 (56.5%) of Cohort C patients were EOC MRD+, most patients demonstrated a marked decrement in EOI to EOC MRD with ruxolitinib and consolidation chemotherapy.

After 48h monotherapy treatment by CHZ868, we detected decreased cell viability (20-75% at IC50), which increased in the combination with dexamethasone...Importantly, combination of BIBF1120 and CHZ868 showed a synergistic effect (-45%, at IC50)...Indeed, active caspase 3 increased after ruxolitinib and chloroquine (autophagy inhibitor) combination (+20% vs ruxolitinib alone, p<0.01)...Instead, AT9283 (p<0.001 vs LCLs), Fedratinib (p<0.01 vs LCLs) and Gandotinib (p<0.05 vs LCLs) were found to be potent, specific, and non-toxic JAK2 inhibitors. Additionally, this extended screening led us to identify drugs, not belonging to JAK inhibitors, specific and non-toxic for rearranged JAK2 cohort, such as Birinapant (Smac mimetic), JQ1 (BRD4 inhibitor), Fludarabine (Chemotherapy) among the others. CHZ868 is a promising drug for the treatment of JAK2 fusions. Further studies will focus on effective and specific novel drugs found to be highly effective and specific on JAK2 rearrangements in BCP-ALL.

The genetic heterogeneity parallels the multiple types of specialized B-cells and their specific tissue distribution. Particularly, many recurrent hotspot and damaging mutations in primary cutaneous diffuse large B-cell lymphoma of the leg type, involving MYD88 gene, or BCL6 and MYC translocations and BLIMP1 or CDKN2A deletions are useful for diagnostic and prognostic purposes for this aggressive subtype from other indolent CBCL forms.

Venetoclax (a BCL-2 inhibitor) or AZD5991 (an MCL-1 inhibitor) enhanced the effects of ruxolitinib on Ba/F3-SPAG9-JAK2 in vitro. These findings suggest that activation of the JAK2-STAT1-BCL-2/MCL-1 axis contributes to SPAG9::JAK2-related aberrant growth promotion. BCL-2 or MCL-1 inhibition is a potential therapeutic option for B-ALL with SPAG9::JAK2 fusion.

P2, N=25, Recruiting, Jason Robert Gotlib | Not yet recruiting --> Recruiting | Trial completion date: Jun 2024 --> Oct 2023 | Trial primary completion date: Apr 2021 --> Apr 2023

Ruxolitinib (rux) Phase II clinical trials are underway for the treatment of high-risk JAK2-rearranged (JAK2r) B-cell acute lymphoblastic leukemia (B-ALL)...Using in vitro models of JAK2r B-ALL, JAK2 p.G993A conferred resistance to six type-I JAK inhibitors and the type-II JAK inhibitor, CHZ-868. Using computational modeling, we postulate that JAK2 p.G993A enabled JAK2 activation in the presence of drug binding through a unique resistance mechanism that modulates the mobility of the conserved JAK2 activation loop. This study highlights the importance of monitoring mutation emergence and may inform future drug design and the development of therapeutic strategies for this high-risk patient cohort.

These findings suggest that a subset of CD30+ ALK- systemic PTCL with anaplastic morphology carry JAK2 rearrangements, some of which appear to show CHL-like morphologic features. The presence of JAK2 rearrangements in cases of CD30+ PTCL augments current classification and may provide a therapeutic target via JAK2 inhibition.

Eleven patients received disease-based chemotherapy or hypomethylating agents, three received FLT3 inhibitors, and five patients proceeded to hematopoietic stem cell transplant. Together with a review of 16 cases published in the literature, it is apparent that M/LNs with FLT3 rearrangement show disease features reminiscent of members in the category of M/LN-eo with PDGFRA, PDGFRB, FGFR1, and PCM1/JAK2 rearrangement, characterized by a specific gene rearrangement, frequent eosinophilia, multi-lineage involvement and therapeutic benefit from kinase inhibitors.

Accurate diagnosis and classification of this category of myeloid/lymphoid neoplasms has important therapeutic implications. With the large number of submitted cases, we expand our understanding of these rare neoplasms and improve our ability to diagnose these genetically defined disorders.

PDGFRA/B-rearranged patients usually manifest as imatinib-sensitive myeloproliferative neoplasms (MPNs)...If these are excluded and a secondary cause is not identified, a diagnosis of idiopathic HES and/or other rare variants of HES should be considered. This review, through an illustrative case, summarizes current knowledge on HES pointing at new directions in diagnosis and treatment.

Myeloid/lymphoid neoplasms with PDGFRA , PGDFRB , FGFR and PCM1 - JAK2 rearrangement or mutations can present as a variety of hematologic neoplasms. Additional cytogenetic abnormalities were present in a subset of patients. Accompanying mutations involving other myeloid associated genes were usually present, and may play a role in response to the treatment and clinical outcome.

In conclusion, this report describes a novel STRBP-JAK2 gene fusion in a Ph-like ALL patient with a very aggressive disease course, which proved resistant to chemotherapy combined with ruxolitinib but sensitive to immunotherapy. Our study suggests that CAR T-cell therapy may be a viable option for this type of leukemia.

These patients appear genetically distinct to younger adults with primary genetic abnormality unidentified in a significant proportion. Hence the need for further genomic studies in older adults.

Cytotoxicity assays on primary clinical DS-ALL samples demonstrated that, regardless of mutation status, high-risk leukemic cells could only be killed using RAS-inhibitor or PTPN11-inhibitor, but not PI3K/JAK-inhibitors, suggesting a unified treatment target for up to 80% of DS-ALL. Importantly, protein activities-based principal-component-analysis multivariate clusters analyzed for independent outcome prediction using Cox proportional-hazards model showed that protein-activity (but not mutation-status) was independently predictive of outcome, demanding a paradigm-shift in patient-stratification strategy for precision therapy in high-risk ALL.

P1, N=15, Active, not recruiting, University of Chicago | Not yet recruiting --> Active, not recruiting